st/mesa: add ST_DEBUG=wf option which enables wireframe rendering

Useful for tessellation.

src/mesa/state_tracker/st_atom_rasterizer.c

@@ -33,6 +33,7 @@
 #include "main/macros.h"
 #include "st_context.h"
 #include "st_atom.h"
+#include "st_debug.h"
 #include "st_program.h"
 #include "pipe/p_context.h"
 #include "pipe/p_defines.h"
@@ -119,8 +120,14 @@ static void update_raster_state( struct st_context *st )
    /* _NEW_POLYGON
     */
    {
-      raster->fill_front = translate_fill( ctx->Polygon.FrontMode );
-      raster->fill_back = translate_fill( ctx->Polygon.BackMode );
+      if (ST_DEBUG & DEBUG_WIREFRAME) {
+         raster->fill_front = PIPE_POLYGON_MODE_LINE;
+         raster->fill_back = PIPE_POLYGON_MODE_LINE;
+      }
+      else {
+         raster->fill_front = translate_fill( ctx->Polygon.FrontMode );
+         raster->fill_back = translate_fill( ctx->Polygon.BackMode );
+      }
 
       /* Simplify when culling is active:
        */

src/mesa/state_tracker/st_debug.c

@@ -55,6 +55,7 @@ static const struct debug_named_value st_debug_flags[] = {
    { "query",    DEBUG_QUERY, NULL },
    { "draw",     DEBUG_DRAW, NULL },
    { "buffer",   DEBUG_BUFFER, NULL },
+   { "wf",       DEBUG_WIREFRAME, NULL },
    DEBUG_NAMED_VALUE_END
 };
 

src/mesa/state_tracker/st_debug.h

@@ -46,6 +46,7 @@ st_print_current(void);
 #define DEBUG_SCREEN    0x80
 #define DEBUG_DRAW      0x100
 #define DEBUG_BUFFER    0x200
+#define DEBUG_WIREFRAME 0x400
 
 #ifdef DEBUG
 extern int ST_DEBUG;